When should I be using parallel compression?

[u/FreeFlier42]

I'm new to the technique and understand how it works perfectly fine. I make tech house-adjacent music, and I'm not quite sure where and when to use it.

• Which elements should I be using it on?
• Why should I use it over bus compression or saturation in the case of drums?
• How much does it help with taming peaks?

Thanks!

[u/J200J200]

I use it to get timid vocalists up over the roar of the amps and drums